Effective bi-linear resistance function

REffective stiffness kE is selected such that the areas under the resistance-displacement graphs are equalM0 M0

k2M0 (yel)1 < y < (yel)2 M0

RmM0 (yel)2 < y < ym

R1kE

k10 < y < (yel)1

(yel)1 (yel)E (yel)2

ym

Resistance function with softening

R R2 k2 R1 R3 R4 k3 k4

k1

Moment capacity of panels based on static design

250 Moment (kNm) 2% reinforced (#1) 200

2% unreinforced (#2) 150

4% hybrid fibres unreinforced (#3)

100

50

0 0 0.0002 0.0004 0.0006 0.0008 0.001 Curvature (1/mm)

Resistance functionsResistance vs Deflection120

Resistance vs Deflection120

Resistance vs Deflection120

Panel #1/4

Panel #2

Panel #3

100

100

100

80

80

80

Resistance

Resistance

60

60

Resistance0 50 100 150 200 250

60

40

40

40

20

20

20

0 0 50 100 150 200 250 300 350

0 0 50 100 150 200 250

Deflection

Deflection

Deflection

250

Moment (kNm)

2% reinforced (#1)

200

2% unreinforced (#2) 150

4% hybrid fibres unreinforced (#3)

100

50

0 0 0.0002 0.0004 0.0006 0.0008 0.001 Curvature (1/mm)

Autodyn prediction of Panel #1 2% fibres / reinforced / 9m stand-off

100

SDOF: 117 mm @ 25 msec

Summary UHPFRC achieved superior performance over standard concrete Increasing fibre content increased both flexural strength and toughness but the increase was disproportionate Forced orientation of fibres close to the moulded surfaces of test specimens was found to have no effect on flexural strength UHPFRC panels performed well in both small-scale and fullscale explosion tests with no rear-face spalling